While reading another topic and following some posted old reference links I came across the use of zinc metal, when inserted into a batch of too old, too red collodion to decolorize it.

This was found in "Notes and Queries", the "Restoration of old Collodion". This note provided by a Mr. Hautes Pyrenes Luz, which appears to be more likely a nom de plume.

It is a direct reaction occurring in refluxing ether (gives me nightmares to think of that one) or in aqueous solutions.

Zn + I2 = ZnI2

This seems very interesting and an alternate to using admixtures of acetone which for some folk may give rise to later issues with dissolving collodion during varnishing with materials containing further solvents or eluents.

Has anyone tried this in recent times with good or bad or indifferent results?

Regards

Matador Mac

Mark MacKenzie, M.A.C.
Art Conservator
Alcalde, New Mexico

a.ka.a. Matador Mac, SASS Duellist
But would like to be a wet-plate practioner.